DOCUMENTATION AND RECOVERY OF RUPESTRIAN PAINTINGS: 
AN AUTOMATIC APPROACH 
José Luis Lerma 
Departamento de Ingeniería Cartográfica, Geodesia y Fotogrametría, Universidad Politécnica de Valencia 
C° de Vera, s/n. 46071 Valencia, Spain 
Phone: ++34-963877550, Email: jllerma@cgf.upv.es 
KEY WORDS: Archaeological Photogrammetry, Spectral Classification, Multiband Classification, Rock Art 
ABSTRACT 
This paper describes an automatic approach in archaeological photogrammetry for the documentation and recovery of rupestrian 
paintings. Visible and near-infrared images were taken from an opened-cave before and after moistening the stone wall. Digital 
image processing techniques, specially multispectral and multiband classifications, were used to recognise and extract non- 
destructively the primitive paintings and shapes, i.e. arrows, hunters and animals. 
Images of rupestrian paintings are presented, before and after human restoration. Additionally, thematic plots of work art obtained 
semi-automatically and independently before the cave restoration are shown in order to check the profitability of the methodology; 
statistical accuracies are also presented. Furthermore, some guidelines for future documentation and recovering of rupestrian 
paintings are pointed out. 
1. INTRODUCTION 
Rupestrian paintings are a valuable legacy that should be well known and safeguarded for future generations. Each set of rock 
paintings has a universal relevance as exceptional cultural expression, and they constitute an important part of the whole rock art. 
Particularly, levantine rupestrian cave paintings keep certain features: high fragility and vulnerability; inner and outer beauty (the 
former refers to the paintings themselves and the latter to the natural environment). Most of levantine rock paintings are placed in 
opened areas, i. e. opened-caves, that offer unsuitable conditions for protection. On the one hand, human vandalism is a negative 
factor: paintings are sometimes overpainted (graffitis) or just partially extracted. On the other hand, weather effects (for instance, 
high temperature variation, acid rain and pollution) as well as geodinamical processes produce slow but continuous alterations. 
Photogrammetry is an optimal way of plotting archaeological sites, either from aerial images or from terrestrial photographs 
(Perdrizet, Grussenmeyer, 1997); there are lots of experiences within CIPA dealing with this subject, and one specific working 
group! The digital era offers new possibilities within this field, not only for the automatic capture of points, lines, and subsequent 
creation of orthoimages, virtual models, etc., but also for the identification and recognition of surface features. This paper describes 
an automatic approach in archaeological photogrammetry for the documentation and recovery of rupestrian paintings. 
The methodology presented herein uses multispectral photography, as pointed out by Vicent (1996), and applies digital multiband 
classification (Lerma, J.L., 2001). This choice gets exhaustive data from photographs in order to get thematic maps for cave paintings 
(mainly pigments and stones). This way of graphical documentation follows a different approach compared to traditional tracing. It is 
quick and objective, and offers the possibility to extract non-destructively the primitive paintings prior to restoration tasks. 
2. ARCHAEOLOGICAL SITE AND FEATURES 
The archaeological site is a piece of the Civil cave {'Cova Civil') located on the Valltorta ravine (Tirig, Castellón, Spain). Some 
qualities of this cave belong to the levantine rock art, i. e. naturalistic rock art with a large variety of drawings: mainly hunting, 
harvesting and warlike scenes, although there are also agricultural and farm ones. The greatest part of figures are red monochrome, 
representing men and women; animals, objects and abstract motives also appear but they are less important (Arte Rupestre, 1999). 
The most important feature to be identified within the scene is the reddish pigment, although there are also further features, for 
instance, oxide and calcareous stones. The reddish pigment shows the primitive paintings and shapes, i. e., hunters, arrows and 
animals. 
After a direct observation of the cave and depending on characteristics such as material, colour, texture and relevance, several 
archaeological features are identified: (1) (reddish) pigment, (2) (yellowish) oxide, (3) whitish stone, (4) rosy stone, (5) reddish stone, 
(6) brownish stone, and (7) darkish stone. 
Proceedings 18 th International Symposium CIPA 2001 
Potsdam (Germany), September 18 - 21, 2001